DE3127302C2 - "Device for propulsion control on motor vehicles" - Google Patents

Abstract

A device for regulating propulsion on motor vehicles is specified which, in addition to optimally utilizing the output torque of the vehicle's drive unit in critical driving situations, especially under extreme road conditions, also provides good vehicle stability and increased driving safety. Accordingly, in a propulsion control device according to the invention shown in its basic features, a comparison device responding to at least one predeterminable or fixed predetermined threshold value of the vehicle speed is provided, which, as soon as this threshold value is exceeded and indicates the activation of an individual wheel brake or the tendency to spin one of the driven wheels Signal is present, an output signal mediating the reduction of the drive torque is generated. The relevant threshold value of the vehicle speed is preferably regulated as a function of the transverse acceleration acting on the vehicle when cornering.

Description

P = ——

• mg

r _m 2μ ₄ Fy

those for evaluating the relationship

E = kV

required pressure output signals p generated.

25. Device according to one of the preceding claims, characterized by its design as an accessory to one on the vehicle existing 4-channel anti-lock device. de-. '■> Ren speed sensors (16 to 19) and their provided for the driven vehicle wheels (13 and 14) Brake pressure control valves (23 and 24) as part of the propulsion control device (10; 140) are used analogously. in

26. Apparatus according to claim 25, characterized in that the evaluation circuit (141) suitable for controlling the brake pressure control valves (23 and 24) pressure-increase, pressure hold and pressure reduction signals rte from a η linking for different W "Ai and A : of the slip of the driven wheels (13 and 14) ΐΛαίη fiit · <jer "n""^" - "^" ku ,,,,; ,, .. ,,,. .. "λ ,," ,.

delay characteristic (+ b) - and (-b) - threshold value signals generated according to the conditions:

(i) Generation of the pressure build-up _{signal if there is an A 2} signal or a (~ 6> in combination with an Ai signal or a (+ 6> signal in ■ »"> combination with an A ₂ signal):

(ii) Generation of a pressure hold signal when a (-1-6 / or an A; signal is present and

(iii) Generation of a pressure reduction signal when a (-6> signal or a (-6> signal in combination with an A _; signal or a (-6> signal in combination with an Ai signal) is present (Fig . 5a and 5b).

The invention relates to a device for regulating propulsion on motor vehicles in the sense of prevention an undesired spinning of the cdriven vehicle wheels with the others in the preamble of claim 1 features mentioned.

A device of this type is described in DE-PS 06 671 in connection with a four-wheel vehicle with two driven and two non-driven & 5 Wheels known.

In the known device, each wheel is provided with an electrical output signal proportional to the wheel speed generating speed sensor. For processing the wheel speed output signals of the Speed sensors are provided with two differential amplifiers, which receive the wheel speed signals as input signals of the driven and the non-driven wheel each received on one side of the vehicle. The output voltages the differential amplifier are then each the difference between the speeds of the driven and the non-driven wheel on one side of the vehicle and thus essentially the slip on this side located driven wheel proportionally. With the slip-proportional output signals of the differential amplifier an electronic switch is activated each, which, when a certain signal level of the associated differential amplifier output signal switches through, whereby an electromagnetically actuatable Brake control valve controlled in its open position and thereby the wheel brake cylinder of the driven wheel of the relevant side of the vehicle uruckbeaufschiagt and this wheel braked thereby; will. A threshold value is specified by means of a suitable resistor circuit in the differential amplifier achieved in such a way that the activation of the respective wheel brake only takes place when a certain Minimum wheel slip of e.g. 15%. this minimum value being dependent on the speed can be reached or exceeded. In a special design of the well-known propulsion control device becomes with dt.n output signal of the differential amplifier, which triggers the activation of the wheel brake of the wheel tending to spin, at the same time control a torque-reducing intervention in the drive unit of the vehicle. This kind of Propulsion control has the disadvantage that in driving situations such. B. when starting on a hill, in where the exploitation of the highest possible propulsive torque is desired. often just one nnnannntnujot ΠΓρΚϋΙΛΙΠΡΠΐ 711Γ Vppfl'iaiini7 Qtpht IJ ΓΠ

To avoid this disadvantage is a further design of the known propulsion control device - The design from which the preamble of claim I was based - provided that the output signals of the two differential amplifiers as input signals to a two-input AND logic element are supplied, and that only through the output signal of this AND logic element Actuator is activated, which, as long as this output signal is present, a reduction in the torque the drive unit mediated, z. B. by switching off the ignition or by intervening in the Fuel supply to the engine or by adjusting the throttle valve (e-gas).

The known propulsion control device conveys an efficient implementation of the in this design Output torque of the drive unit into a propulsion torque that accelerates the vehicle and in this respect an optimization of the z. B. when starting or overtaking exploitable vehicle acceleration. the the type of propulsion control implemented here with a first - fast - control circuit, the one when the a predetermined slip value of the drive wheels on one or the other side of the vehicle, their wheel brakes activated, and with a second control loop which intervenes in the drive unit and which only responds when the specified slip limit value has been reached or exceeded on both sides of the vehicle - and thus in of all rule is much slower than the first control loop - but has the disadvantage that the

3 \ 27 302

Vehicle just clinch the effect of the familiar Control device can get into a dangerous driving situation. Such is with a vehicle Rear axle drive z. B. then given when on wet road the frictional connection between the driven wheels and the road surface is small and the driven wheels already have a relatively high one Slippage are retained, which, however, is still below the response threshold of the propulsion control. if now the vehicle goes from straight ahead to cornering, this increases because of the When cornering, the load on the inside drive wheel is relieved of its tendency to spin. Now he speaks to the wheelbrcni.se of this rear wheel active control loop, this / was braked and thereby its slip is reduced, at the same time however, due to the differential effect, the effective torque on the rear wheel on the outside of the bend is increased, which inevitably leads to the fact that when cornering for the .Seitenführung more substantial drive wheel on the outside of the curve, an increase in the slip and thus a deterioration its lateral guidance properties occurs, with the result that the vehicle swerves before even on Outside rear wheel of the curve, the slip limit value, which is decisive for the response of the propulsion control, is reached is.

Similar dangerous situations can also be triggered when cornering has already been initiated the coefficient of adhesion that can be used on the drive wheels is strong due to the condition of the roadway Are subject to fluctuations.

The object of the invention is therefore to provide a device of the type mentioned, which, without Impairment of the propulsive acceleration that can be used when driving straight ahead, in cornering situations conveyed increased driving stability.

According to the invention, this object is achieved by the characterizing features of claim 1 solved.

According to this, the propulsion control device according to the invention generates - in the sense of a "select low" operation - the output signal that reduces the drive torque when cornering when only one of the drive wheels tends to spin and at the same time a threshold value v _s ι of the vehicle speed is exceeded.

The essential advantage of the propulsion control device according to the invention resulting from this is a suitable specification of the travel speed threshold value v _s , provided that in the range of the higher travel speeds v> v _s , ie in the speed range in which when cornering or when transitioning from When driving straight ahead into a cornering, instability of the driving behavior could have dangerous effects and, because of the lateral accelerations acting on the vehicle, a reduction in cornering ability cannot be accepted, a significant improvement in vehicle stability is guaranteed

Curve detection devices are known (DE-OS 2108 592 and DE-PS 9 31633 and US-PS 32 88 232) in the sense of achieving a minimum driving stability a cornering dependent control the output torque of the vehicle drive unit (DE-OS 21 08 592) or the torque transmission behavior one in the drive train

of the motor vehicle provided differential gear (DE-PS 9 31 633) mediate or in a propulsion control device (US-PS 32 88 232), the evaluation circuit of the spinning tendency of a drive wheel recognizes from different wheel speed sensor output signals, prevent cornering-related Wheel speed differences inte retiert from this evaluation circuit in the sense of a spin tendency will. These known curve detection devices are always in one used other than the function provided according to the invention. Furthermore it is in connection with one that works with torque-reducing intervention in the drive unit of a motor vehicle Propulsion control device (DE-AS 21 31 536) also known, the slip control only above a - low - driving speed threshold, which is specified in the DE-AS with 3.2 km / h. take effect too let, with this low switch-on threshold only to prevent that in a start-up situation odor at a z. B. to overcome a Snowdrifts required slow forward and backward movement of the vehicle, causing the engine to stall is prevented.

In contrast to this, with the propulsion control device according to the invention, if the speed threshold v, \ is exceeded when cornering, the control device is switched from a control behavior aimed at optimal propulsion acceleration below this threshold value to a control behavior that provides optimal driving stability above this threshold.

The threshold value v _s \ should therefore be set in the manner of the best possible compromise between optimal propulsive acceleration and driving safety so that - as required - a sufficiently wide low-speed range is available in which an optimal vehicle acceleration or propulsive force can be used, however, this threshold v _s for the select-low operation is still sufficiently low to reliably avoid dangerous driving situations.

The value of approx. 40 km / h specified in claim 2 as the speed threshold y _s ι represents a favorable design of the propulsion control device according to the invention in terms of the best possible compromise explained above.

While cornering at relatively low speeds and relatively large curve radii, significant lateral accelerations occur and correspondingly high cornering forces are required to ensure the directional and driving stability of a vehicle this is very much the case when driving straight ahead, during which no transverse accelerations act on the vehicle much lower cornering forces are sufficient. When driving straight ahead, the Driving stability a torque-reducing intervention in the drive unit only at very much higher values driving speed than when cornering.

Therefore, in a further embodiment of the invention Propulsion control device according to claim 3 is provided that when driving straight ahead the "selectlow" mode the propulsion control device becomes effective when a second, higher speed threshold value Vj2 from z. B. 100 km / h is exceeded and further a braking tendency of one of the driven vehicle wheels indicating the tendency to spin

Control signal is present.

Due to the features of claims 4 to 6 are common means of analog and / or digital electronic Circuit technology realizable designs of the electronic signal processing and the signal linking part specified the propulsion control device according to the invention. The advantage of this circuit design is that a z. B. as part of an antiblocking device already present on the vehicle provided signal processing circuit, which the wheel speed proportional sensor output signals to wheel-speed and wheel-acceleration-proportional suitable for further processing, as well as for the slip of the driven vehicle wheels characteristic Aus ι> input signals processed, also in the context of the propulsion control device according to the invention zwekkanalog can be used. This can therefore, if there is an anti-lock device on the vehicle, in terms of their electronic circuit part as a relatively simple and inexpensive additional device be designed so that the additional costs to be used for the propulsion control device only about 10 to 20% of the price of an anti-lock device.

Due to the features of claims 7 to 9, within the scope of the propulsion control device, If necessary, designs of cornering detection devices that can also be used in combination specified, from the difference in the wheel speeds jo of the non-driven vehicle wheels and / or the Detection of the lateral acceleration acting on the vehicle or by monitoring the for a Cornering characteristic position of a part of the steering generate a cornering display signal.

As far as such cornering detection devices as provided according to claim 10, a transverse acceleration proportional Generate output signal, this can, as indicated by the features of claim 11, advantageously to a needs-based change in the speed threshold value are used, above which the select-low operating mode of the propulsion control device is effective.

Additional security in the sense of the keeper-ti The stability of the vehicle can also be achieved by a circuit device provided according to claim 12, which triggers a torque-reducing intervention in the drive unit of the vehicle when the vehicle acceleration values preferably determined from the wheel speeds of the non-driven vehicle wheels exceeds a critical threshold. This effectively becomes a dangerous situation prevented, which z. B. can arise when the vehicle is in a driving situation with high Propulsion acceleration and thus also relatively high slip of the driven wheels is located and with There are considerable fluctuations in the adhesion coefficients associated with road conditions. It is there advantageous if the device according to claim 13 so is designed that this acceleration-dependent control of the engine torque only above one given threshold of the vehicle speed of e.g. 20 to 30 km / h is effective, so with When moving off, the maximum possible propulsion acceleration can still be exploited

A propulsion control device which is subject to the basic idea of the invention can in principle also be implemented in the design outlined by the features of claim 14, the acceleration here the driven vehicle wheels is used as a reference variable. So much for such a control system not in and of itself the essential requirements of an effective propulsion control device is sufficient, it mediates at least in combination with the embodiments explained above additional safety and driving stability.

The specified by the features of claim 15 Dimensioning of the supply pressure source for the propulsion control according to the invention ensures, that this also occurs in the case of large differences in the adhesion coefficients effective on the driven wheels works reliably.

By means of the shutdown provided according to claim 16, the driver can, if he z. B. in "Power-slide" wants to drift in a curve, the propulsion control for a defined period of time inoperative set.

By a protective device provided according to claim 17, which automatically acts on the brake system Acting functional part of the propulsion control device switches off, it is prevented that in a frequent response of the propulsion control, the rear brakes overheat. Such a protective device is of great importance for the operational safety of the braking system.

The design and arrangement of temperature sensors specified by the features of claim 18 has the advantage that the brake disc temperature can be recorded very precisely and, in this respect, its thermal Resilience can be largely exploited.

The features of claims 19 to 21 provide alternatives to this, possibly also in combination Exploitable arrangements of temperature sensors are given, which are particularly easy to implement structurally are.

The information required for a protection shutdown of the propulsion control device about the information in the respective wheel brake accumulating or stored amount of heat can also by a according to claim 22 provided circuit arrangement can be obtained from an evaluation of the brake fluid pressure in the wheel brake cylinders and the wheel revolutions of the braked wheels generates a signal that the corresponds to work converted into heat during braking.

Brake mean pressure proportional to suitable for evaluation electrical signals can be generated by means of suitable sensors (claim 23) or, as in claim 24 indicated by electronic evaluation of the vehicle acceleration or the acceleration of the driven wheels and thus ultimately through an evaluation of the output signals proportional to the wheel speed the speed sensor can be obtained, with the particular advantage that the one with the pressure sensors there is no need for any associated mechanical or technical effort.

Further details and features of the propulsion control device according to the invention emerge from the description of special embodiments with reference to the drawing. It shows

F i g. 1 is a greatly simplified block diagram of a first, simple embodiment of one according to the invention Propulsion control device,

2 shows a block diagram of the electronic evaluation circuit part a preferred embodiment of a with regard to its basic structure

bixii-rs the LinrichUing according to Fig. I corresponding propulsion control device,

F i g. 3 shows a block diagram of a circuit part according to FIG. 2 provided Curve η driving detection device.

F i g. 4a to 4c are block diagrams of various, within the scope of the propulsion control device according to FIGS F i g. 1 to 3 usable protective devices and

Fig. 5a with 5b the logic circuit of a specially in combination with an anti-lock device suitable embodiment of a propulsion control device according to the invention.

For the illustrated in FIG. 1, to the details of which reference is expressly made, according to the invention Propulsion control device 10 is - without loss of generality - a design for A rear-wheel drive vehicle is required, which is also equipped with a 4-channel anti-lock device (ABS system) is provided, the front wheels of which Il and 12 and wheel speed sensors 16 and 17 and 18 and respectively associated with the rear driven wheels 13 and 14 19 and 'eren for the rear wheels 21 and 22 Brake pressure control valves 23 and 24 provided for the propulsion control device 10 are also used.

These control valves 23 and 24 are designed as magnetically controlled ^J / 3-way valves in accordance with their function in the ABS system.

22 are connected to the brake line 49, via which the brake pressure is built up. By a control current signal / 1 of z. B. 2 A are the brake pressure control valves

23 and 24 in their blocking position corresponding to the pressure holding phase and by a control current signal / 2 from z. B. 4 A can be controlled in their return position corresponding to a brake pressure reduction phase, in which, as schematically indicated by means of the return pump 25 provided as part of the ABS system from the wheel brake cylinders into the brake line 49 or the master brake cylinder (not shown) is funded back.

The central component of the propulsion control device 10, which is essential to the invention, is its overall number 26 designated electronic evaluation circuit, which consists of a to be explained in more detail below Processing of the wheel speed-proportional output signals from the speed sensors 16 to 19 is one of them Braking appropriate to the driving situation of the driven rear wheel 13, which tends to spin or 14 or a reduction in the output torque of the drive unit (not shown) generating triggering control signals for the actuating and switching elements provided for this purpose.

The evaluation circuit 26 has as an input stage a signal processing stage 27 with four inputs at which one of the speed sensor output signals / Vr, / hr, / Vz. and / hz. is received, again assuming, without loss of generality, that these signals are electrical pulse trains with a pulse train frequency proportional to the wheel speed /. The signal processing stage 27 processes these input signals into a first output signal characteristic of the amount of slip Xr of the right, driven rear wheel 13 and a second output signal characteristic of the slip Al of the left, driven rear wheel, which is sent to the two outputs 28 and 29 of the processing stage be delivered. The XR and λΖ, signals are made from the difference between the wheel speeds of the right

and the left side of the vehicle. Next, the preparation stage 27, z. B. by averaging or summing the wheel speeds of the non-driven front wheels 11 and 12 at their third output 31 an f output signal proportional to the vehicle speed ν. The two XR and ΑΖ, output signals of the processing unit 2 '/ are ie a comparator 32 and 33 as input signals.' which compare these signals with an assigned threshold value Xm , which represents a maximum value of the slip on the driven wheels 13 and 14 that is considered to be permissible. As soon as the slip Xk or λ; of one or the other driven wheel 13 or 14 reaches or exceeds this threshold value Xm , the comparators 32 and / or 33 emit a high-level output signal. Furthermore, a third comparator 41 is provided within the scope of the comparison device, comprising the two slip value comparators 32 and 33 and denoted as a whole by 39, which emits a high-level output signal as soon as the vehicle speed ν reaches a predefined od <; r suitably predefinable threshold value v _s i reached or exceeded.

The output signals of the comparators 32, 33 and 41 of the comparison device 39 are used as input signals a logic circuit provided as part of the evaluation circuit 26 and designated overall by 42 forwarded, from the linkage to be explained in more detail below Combinations of the comparator output signals at their outputs 37 and 38 for the appropriate Control of the wheel brakes 22 and 21 required control signals for the brake pressure control valves 24 or 23 and at the outputs 43 and 44, possibly also only at a common output Outputs control signals with which the reduction in the output torque of the drive unit can be controlled.

The logic device 42 comprises a total of five 2-input AND elements 46, 47, 48 as well as 34 and 36; the outputs of the two A ^ / comparators 32 and 33 are connected to the two inputs of the first AND element 46. The inputs of the second AND element 47 are each the output of the first A, \ r comparator 32 and the output of the v ₅ , -, comparator 41 and the inputs of the third AND element 48 are each the output of the second Am- Comparator 43 and also the output of the v _S i comparator 41 are connected.

With the output signals present at the outputs 43 and 44 of the logic device 42 these AND gates 46, 47, 48 are the torque-reducing intervention in the drive unit controlled by the vehicle.

The two other 2-input AND elements 34 and 36 receive the output signal of one of the two A _A comparators 32 and 33 at their one input and the inverted output signal of the other at their other input via an inverter 35 and 45, respectively of the two λΛγ comparators 33 and 32. With the pending at the outputs 37 and 38 of the logic circuit 42 output signals of the two further AND elements 34 and 36, the brake pressure control valves 24 and 23 can be controlled in their blocking position. Driver stages that may be required for this are not shown for the sake of simplicity.

A 2-unit OR gate 51 is also provided.

hen, to which the output signals of the AArComparators 32 and 33 are fed directly.

The propulsion control device explained so far works as follows:

If one of the driven rear wheels 13 or 14 begins to spin, it will triggered output signal of the first or the second ÄM comparator 32 or 33 or the output signal of the directly downstream AND element 34 or 36, the brake pressure control valve 24 or 23 of the respective other, not spinning rear wheel 14 or 13 from its basic position in which the respective wheel brake cylinder communicates with the brake line 49 of the rear axle brake circuit, in its locked position controlled while the brake pressure control valve of the spinning wheel remains in its basic position At the same time, by means of the output signal of the OR gate 51, a Schah valve arrangement 52 in FIG whose conduction direction is controlled in the direction of brake line 49 denoted as a whole by 53 Dnickquelle for an activation of the wheel brake the spinning wheel has a sufficiently high pressure level connected. Both give A «comparators 32 and 33 produce a high level output. d. H. when both driven wheels 13 and 14 to If you spin aeigen, the output signal of the first AND element 46 is also a high-level signal with the now an actuator is controlled. the said reduction in the output torque of the drive unit conveyed. Because of the negation of the respectively mediated by the inverters 35 and 45 an input signal of the AND gates 34 and 36 is their output signal as long as both A * r comparators 32 and 33 produce their high level output, a low level output. d. H. the brake pressure control valves 23 and 24 are in their basic position, in which both wheel brakes 21 and 22 are activated.

This type of propulsion control is effective as long as the vehicle speed ν is less than the comparison threshold value v 1, of the third comparator 41.

If this threshold value is reached or exceeded, an output signal which reduces the output torque of the drive unit is output at the common output 43 of the two AND gates 47 and 48 as soon as one of the two driven wheels 13 or 14 begins to spin. The propulsion control device 10 operates below the threshold value v, in the sense of optimizing the vehicle acceleration, and above this threshold value in the sense of optimizing the driving stability.

In a preferred embodiment of the propulsion control device 10 according to the invention, it has an evaluation processing circuit 56 in more detail that of FIG. 2. Reference is expressly made to the details of which. apparent structure, the evaluation circuit 26 according to FIG. 1 completely in the evaluation circuit 56 according to FIG. 2 is included.

Accordingly, in both Figs. I and 2 functionally identical or functionally analogous elements or units are each given the same reference numerals. The signal processing stage 27 of the evaluation circuit 56 comprises an input stage 58 controlled by means of a clock 57, which within successive cycle time intervals of equal duration Δι predetermined by the clock time of the clock 57. the output signals of the wheel speed sensors 16 to 19 received at their inputs are processed into the output signals f _RV , / * / * fi_v and Flh, which are proportional to the wheel speed, the / signals at the outputs 61 to 64 of the input stage 58 being characteristic of that cycle time interval At that expired before the cycle time interval that was just running

For the purpose of explanation it is assumed that the input stage 58 as well as the other functional elements and units of the evaluation circuit 56 designed as digital-electronic circuit units are. In this case the output signals of the input stage 58 are e.g. Frequency counter provides characteristic bit-signal combinations. The outputs of each of these counters are in FIG. 2 by only one of the outputs 61 to 64 for the sake of simplicity of illustration represents

The signal processing stage comprises a total of five output stages 66 to 70. those at the outputs 28 to 31 as well as 71 and 72 of the signal processing stage 27 each one of the in the comparison device 39 further to processing slip, travel speed, radial acceleration and output signals proportional to the vehicle acceleration.

The two output stages 66 and 67, which generate an output signal characteristic of the slip Xr and X _{L of} the right and left driven wheel, respectively, are each used as a difference generator z. B. designed as a forward / backward counter, which as input signals, the two wheel speed signals / «ν and / R / fbzw. 4vund /j. wh are forwarded.

The output stage 68 emitting the output signal proportional to the driving speed at output 31 can, for. B. be designed as a summing circuit which sums the fav and / tv signals pending at the outputs 61 and 63 of the input stage 58 for each cycle time interval Δ t .
The output stage 69 provided for recognizing cornering of the vehicle can in the simplest case also be designed as a differential circuit that generates a cornering proportional to the difference between the fgy and 4v ~ signals determined for the non-driven front wheels of the vehicle, which are necessarily different when cornering. Detection signal generated.

The output stage 70 provided for detecting the acceleration of the vehicle in the direction of travel is designed as a dividing circuit, which also receives the (rv and / Ίν signals characteristic of the wheel speeds of the non-driven front wheels as input signals and corresponds to the amount of the expression (7i? V + 4v / ^ i-proportional output signal at output 72 emits.

The cycle times of the output stages 66 to 70 are also shown in dashed lines, as indicated by the corresponding ones Control lines 73 indicated, synchronized by means of the clock 57.

In the context of the comparison device 39, in addition to the XR-. XL and v comparators 32, 33 and 41 whose function in the context of the evaluation circuits 26 and 56 according to FIGS. 1 and 2 is completely analogous. four further comparators 76 to 79 are provided, the processing cycle times of which are also synchronized by means of the clock generator 57 of the signal conditioning stage 57.

These further comparators 76 to 79 generate a high-level output signal when the

the input signal passed to them exceeds a certain threshold value:

The threshold values £ r for cornering detection (comparator 76), v _s2 for straight-ahead driving (comparator 77), V ₃ for the starting phase of the vehicle s (comparator 78) and Bm for straight-ahead acceleration (comparator 79) are selected in this way that the output signal of these comparators represents an indication or a measure that the vehicle is in a situation that requires a change in the control behavior of the propulsion control device 10 for safety or expediency reasons. Comparator 41 is set in a typical case to a threshold value vii of approx. 40 km / h and the second vehicle speed comparator 77 is set to a typical threshold value v $ 2 of approx. 100 km / h.

The logic device 42, which generates the control output signals required in the sense of the control behavior of the propulsion control device 10 according to the invention from a suitable logic combination of the high-level comparator output signals of the comparison device 39, in addition to the control output signals required with reference to FIGS. 1 already explained components 46, 47-48 and 51 two further two-input AND gates 81 and 82, which each have the output signal of the Vs comparator 77 at their one input and the output signal of the Aiw comparator 32 and at their other input of the am comparator 33 received. The outputs of these two AND elements 81 and 82 are connected to a common output 83 of the comparison device 42. A high-level output signal present at this output 83 triggers a reduction in the output torque of the drive unit. A relay 84 can be controlled with the output signal of the cornering signal comparator 76, which has an opening _{contact 87 in the common input line 86 of the two AND elements 81 and 82 and an AND which can be connected to the V 5} comparator 41 in the common input line 88 of the two -Glieder 47 and 48 has closing contact 89 lying.

With the output of the v ₄ comparator 78, the z. B. is set to a v, - value of approx. 20 km / h, another relay 91 can be controlled, the normally open contact of which is a normally open contact 92, which is open in the rest position. In the working position of the relay contact 92, the output of the travel / acceleration comparator 79 is connected directly to a further output 93 of the linking device 42. An intervention which reduces the output torque of the drive unit is likewise triggered by a high-level output signal deo drive-acceleration comparator 79 pending at this output 93.

The evaluation circuit 56 according to FIG. 2 compared to that according to FIG. 1 additionally mediated Functions are hereafter the following:

The reduction of the output torque of the drive unit in the sense of a »Select-Low« = operation, ie when a certain speed threshold value v _s or V5 is exceeded at the same time and a slip signal is only available for one of the driven wheels, which indicates that this Ziirn by turning & 5 tends of the vehicle takes place when driving straight ahead only above a threshold value v, ₂ h of about 100 km /, while upon turning the lower threshold _si v for triggering the select-low operation of the propulsion controller 10 is largely Furthermore, a torque-reducing intervention in the drive unit is triggered when a critical threshold value of the vehicle propulsion acceleration, which could lead to a dangerous driving situation, is exceeded.This acceleration-dependent propulsion control is ineffective below the low-speed range limited by the speed threshold value V ₁ to get the full company when starting up to be able to take advantage of vehicle acceleration.

In the evaluation circuit according to FIG. 2 explained above, the output stage 69 provided as part of the cornering detection device 69, 76 generates a signal which _{is proportional to the difference / a} -i of the wheel speeds v _{a of} the outside front wheel and ν / of the inside front wheel. This signal is thus according to the relationship-

where r denotes the rolling radius of the front wheels and b the track width, proportional to the angular velocity ω with which the vehicle travels through the curve

The transverse or radial acceleration Zv is effective when cornering the vehicle, if Ä _m denotes the path or cornering radius on which the vehicle's center of gravity moves when cornering due to the relationship

Zv = K _n , ω ² (2)

given. Since the radial acceleration b _r reproduced by the equation (2) has a maximum value for that curve radius due to its quadratic ω-dependency, at which the cornering forces are normally just sufficient to keep the vehicle stable when cornering at maximum speed, the comparison threshold value must , to which the comparator 76 connected to the output stage 69 is set, must be set to a sufficiently low value so that in this most critical driving state mentioned above, the control device reliably switches to its select-low mode as soon as the vehicle starts cornering. On the other hand, this means that when cornering detection is obtained from the difference in wheel speed /, and f, the control device 10 in the majority of cases already goes into the select-low operating state when this is not yet necessary were. (With »a« and »i« the outside and inside of the curve are indices; et.)

In contrast, the one shown in FIG special cornering detection device, which is informally in the evaluation circuit 56 according to FIG. 2 can be inserted, a control of the Transition of the control device 10 into its select-low mode.

This in the illustration of FIG. 3 integrated into the evaluation circuit 56, with a total of 94 designated cornering detection device comprises two squaring stages 96 and 97, which as Input signals each one of the wheel speed signals present at the outputs 61 and 63 of the input stage 58 / ffv or /(.vleited. Each of the square Output signals of the squaring stages 96 and 97, which are proportional to the input signals, are used as input signals

a differential stage 98, the output signal of which is proportional to the amount of the difference \ Prv-Plv \ . This signal is then under the realistic assumption that the lane radius R _{n is} large compared to the vehicle width b , in a very good approximation of the effective radial acceleration b _r proportional.

In the following, with "a" and "i" are again the The outside and inside of the curve are indicated Ό

If v _a and v denote the circumferential speeds of the non-driven front wheels 11 and 12, the following applies:

'inf.T-

(3)

(4)

From (3) <uad (4) it follows immediately:

<öÄ _m . (5)

Multiplication by (1) then gives

4 / rV Ua + //) (/. "//) - R _m " ² = A »(6)

25th

d. h " br " is proportional to the difference between the speed squares of the outside and inside front wheels 11 and 12.

With the aid of the curve recognition device 94, a radial acceleration proportion can thus be achieved solely through electronic evaluation of the output signals of the RaJ speed sensors 16 and 17. read control signal b _{r can be} obtained with which a Vj threshold value generator 99 can be controlled, which in turn provides the comparison signal for a travel speed comparator, e.g. B. the comparator 41 or the comparator 77 is generated, with the output signal of which the select-low mode can be controlled. It is particularly advantageous if the threshold value output signal of the threshold value generator 99 varies with the cornering detection or radial acceleration output signal of the differential stage 98 in such a way that for large values of the detected radial acceleration, the v _s threshold value at approx. 40 km / h and at low values of the radial acceleration b _r is approx. 100 km / h and in between decreases with increasing radial acceleration. so

A cornering detection signal suitable for the propulsion control device 10 explained above can also be obtained in that with an element of the vehicle steering that when driving straight ahead assumes a neutral central position and rotated or when cornering compared to this central position is advanced, e.g. B. the steering segment of a worm-segment steering gear or the steering fork of a screw steering gear an actuator for one electrical switch is motion-coupled, as soon as a certain minimum angle of the steering is present, actuates this switch and thereby triggers the cornering detection signal.

With such a movable element of the steering, a displacement encoder can also be coupled, which is a electrical output signal generated, the deflection of the movable element from its neutral position and thus in a first approximation a mean

The steering angle tx _{m of} the steered vehicle wheels 11 and 12 is proportional

tg a _m = a / R _m

where a denotes the center distance, information about the curve radius R _n * This information can be used in conjunction with the travel speed information that can be obtained from the wheel speeds according to the relationships (3) and (4) by means of a suitable analog or digital electronic evaluation circuit according to the relationship

15th br = (V ₁ + VfIR _n

can also be processed into an output signal proportional to the lateral acceleration, with which an im Within the framework of the propulsion control device 10 provided travel speed threshold value transmitter appropriate to the driving situation is controllable

Suitable transverse acceleration proportions for this purpose electrical signals can also be generated with centrifugal force sensors, in which a sluggishly displaceable in the transverse direction of the vehicle against the return forces of resilient elements Mass is provided whose centrifugal force-dependent deflection from its corresponding straight-ahead travel Rest position is detected by means of known, potentiometric or inductive position transducers.

In order to achieve the best possible propulsive acceleration with the propulsion control device 10 according to the invention, even with large differences in the adhesion coefficients μ «and μι effective on the two sides of the vehicle, it may be necessary to brake the drive wheel that tends to spin with a very large braking force, thus on the other drive wheel , at which the larger coefficient of adhesion is effective, this can be fully utilized.

The following therefore first refers to the most favorable dimensioning of the in this regard Brake pressure source 53 provided for the propulsion control device 10.

For the purpose of explanation, a driving situation is assumed in which the propulsive acceleration is continuously increased and there are very different adhesion coefficients μL and pr on the left and right sides of the road, where μκ <μι. should apply.

For a vehicle with rear-axle drive, the maximum achievable vehicle acceleration then applies:

₌ φ ■ (u _L + _μκ ) / 2
^max 1 (+) / 2 '

(9)

where φ denotes the proportion of rear axle load and χ denotes the elevated position of the center of gravity related to the center distance.

For vehicles with front-axle drive, the relationship corresponding to relationship (9) is:

(10)

In the assumed driving situation, the right rear wheel will spin first.

One denotes with / ι the wheel circumference or vehicle acceleration effective on the vehicle, with m the vehicle mass and with Fi the effective on the vehicle

Mass force and with F _uges \ the total effective circumferential forces on the driven wheels 13 and 14, as well

= F _uges \ = 2

(H) the fluid output pressure of the pressure source 53, μ _{β is} the coefficient of friction of the brake linings, r _{m is} the mean radius of the brake disc and r is the rolling radius of the driven rear wheels 12 and 13:

where Fui denotes the effective circumferential force on the vehicle wheels 13 and 14.By the intervention of the propulsion control and braking of the rear wheel that rotates first, in the selected explanatory example of the right rear wheel 13, its circumferential force is essentially kept at the value F _u \ , but an additional one Increase in the circumferential force achieved on the left rear wheel 14, which in turn reaches the spin limit, whereupon the propulsion control device 10 reacts by reducing the output torque of the drive unit and the circumferential force Fj ₂ on the left rear wheel 14 essentially on the one with the higher adhesion coefficient μι. holds a maximum tolerable value, so that analogous to relation (11) can be used:

F ₂ = mgI ₂ = F _ugcs , = F _a2 + F _ttl (12)

The braking force Fbu to be applied to the circumference of the right - burned rear wheel 13, which is required to brake this wheel so far that the maximum propulsion torque compatible with the adhesion coefficient μ * present there can be used, is then

-p,

(14)

10 from which, taking into account (13), the following relationship emerges:

15 ρ = -

• mg

(15)

results Taking into account the relationship (9), this results for the expression (/ 2 ^ / 1):

25th -I) = φ

V-R

ι _

μ *

(16)

F "y = F ^ ₁ -F ^ ₁ = F ₂ -F ₁ = mg (I ₁ - /,). (13)

(16) inserted in (15) and evaluation of this

For this circumferential braking force, the following applies if with F _k the drawing has the following values: cross-section of the brake caliper piston, ρ the brake

r = 0.302 m
m = 2000 kg

r _a = 0.106 m
g = 10 ms " ²

F _k = 11.34 cm ² δ 38 mm0 μβ = 0.3

as well as the following extreme values of the existing adhesion coefficients:

u _L = 0.9 and μ _Λ = 0.1
results in the required brake fluid pressure

_ 0.302
^P 0.106

0.210

2 x 0.3 x 11.34

2000 · 10 = 1760 N / cm ² «175 bar.

Since this is necessary for processing large differences in the adhesion coefficient left / right required brake mean pressure is greater than. "'er output pressure usually Pressure sources present on the vehicle are within the scope of the propulsion control device according to the invention 10 provided pressure source 53, a pressure booster 101 is provided with which the output pressure level one on the vehicle z. B. for power steering or a level control existing Pressure source can be transformed to the pressure level required for the propulsion control.

Since with large amounts the difference in the adhesion coefficients | μ «- μι. | and / or unreasonable driving the control device 10 responds frequently, it is possible in such cases that the brakes 21 and 22 of the driven Piider 13 and 14 after several times

E =

N ₁ =! *. . _2μβ · F _k ■ U ■

overheat repeated control cycles. It is therefore advantageous if a protective device 100, shown in its basic structure in FIG Due to the latency period, the propulsion control device 10 switches off or switches to the higher speed comparison _threshold v s2, whereby an effective protection of the brakes 21 and 22 is also achieved.

For the work carried out in the wheel brakes 21 and 22, the equation (14) results in the following if U denotes the wheel circumference and N denotes the wheel revolutions occurring during a control cycle:

(17)

where / the consecutive control cycles are indicated.

This energy is first converted into heat and stored in the brake disc (s).
Is referred to with:

W is the energy stored in the brake disks, C is the specific heat of the brake disk material

(about 570Nm / kgK)
AT increases the temperature of the brake discs

Load and
m _s the effective mass of the individual brake disks, to

the following applies to each of the two brakes:
W = C ■ m, ■ Δ Τ

(18)

When 4a shown in Fig. Destaltung the protective device 100 is 102 or 103, z for each wheel brake 21 and 22 is a temperature sensor. B. a NiCr thermocouple is provided whose electrical output signal is a measure of the brake disc temperature T. These thermocouples 102 and i03 are preferably arranged in recesses in the brake linings in which a wear sensor is also arranged. This arrangement of the temperature sensors 102 and 103 is structurally easy to implement and allows, even if only indirectly, a sufficiently accurate detection of the brake disk temperature. The output signals of the temperature sensors 102 and 103 are, after suitable amplification, fed to a temperature signal comparator 104 and 106 , respectively, which generate an output signal as soon as the output signals of the temperature sensors 102 and 103 reach a signal level linked to a critical value 7 ", the brake disc temperature T. The alarm signal which, for example, controls a warning lamp 107 is derived from the ORing of the output signals of the 7V comparators 104 and 106. The output signal of the OR element! 08 provided for this purpose is supplied to a time "!: ed 109 if the output signal of the OR element 108 is present for longer than a latency period ATi , it emits an output signal which triggers the shutdown of the propulsion control device 10. As soon as the output signal of the OR element 108 has dropped again, the propulsion control device 10 is switched on again after the latency period ATt mentioned.

One continues to designate with Pdie by thermal conduction and radiation dissipated power in Nm / s, which is known from heat dissipation measurements. so it follows from the Relationship (17)

^ C

AT + Pt

(19)

30th

J pressure sensors 111 and 112 downstream of multipliers 113 and 114, and these respective downstream summing stages 116 and 117 are activated as long as from the one or the other slip value comparator 32 and 33, the evaluation circuit 56 in accordance with F i g. 2 an output signal is present which indicates that the propulsion control is effective and one or the other wheel 21 or 22 is braked. The cycle times of the multiplier stages 113 and 114 and the summing stages 116 and 117 are synchronized by means of the clock generator 57 (FIG. 2). The multiplier stages 113 and 114 receive as a second multiplier input signal the wheel speed signals fan and Λ «output at the outputs 62 and 64 of the input stage 58 for the driven wheels and generate for each cycle time interval At, a of the product p, ■ fun, and p , ■ fun proportional output signal. The guidance provided for each successive cycle time intervals output signals of the multiplier as long lläS respective LJV.lllüpl * r \ Ctl <paei αΐυι "nujguitgjjigriui" iii is summed up by the respective summing 116 or 117th The outputs of summing stages 116 and 117, the one The measure for the heat stored in the respective wheel brake 21 or 22 are each fed to a comparator 118 or 119 , which in turn emit an output signal as soon as this heat stored in the brakes exceeds a critical threshold value 118 and 119 can take place in the same way as explained with reference to FIG. 4a with reference to the output signals of the comparators 104 and 106 .

The for evaluating the draw (19) by means of the electronic circuit part of the protective device UO according to FIG. 4b required brake fluid pressure information can also be obtained by electronic evaluation of relation (15).

A related ^σ 6 €! ^σ πβίο di ^ itllk

50

55

By specifying a certain critical limit temperature 7 " _s , the value C- m _s ■ AT is then again given.

In FIG. 4b, a protective device 110 operating with the evaluation of relationship (19) is shown in a greatly simplified block diagram:

The wheel brakes 21 and 22 are each equipped with a pressure sensor 11 and 112 , respectively, which generate digital output signals characteristic of the brake fluid pressure. The analog-digital converters required for this are not shown separately. The basic features of the evaluation circuit are shown in FIG. 4c and is briefly explained below based on their function:

At the output 121 of a shift register 122 , the driving acceleration output signals of the vehicle acceleration output stage 70 (FIG. 2) are available with a time delay of approx. 0.3 to 0.5 sec of the one and / or the other driven wheel 13 and / or 14 is determined. As soon as there is an output signal from one of the slip value comparators 32 or 33 which conveys an activation of one or the other wheel brake 21 or 22 , the acceleration information present at output 121 is entered into the / i memory 123 and held there until how the assigned wheel brake is activated. As soon as there is a signal indicating that the second wheel is also tending to spin, e.g. B. the output signal transmitted at the output 38 of the logic circuit 42 , which mediates the reduction of the engine torque, the travel-acceleration information is _{entered in the / 2} memory 124 and at the same time a computer stage 126 is controlled, which thereupon the memory contents of the two memories 123 and 124 processed according to the relationship (15) to the required brake fluid pressure information Das the pressure information p; The output signal of the computer stage containing the output signal can now be used instead of the p, signal obtained by means of the pressure sensors 111 and 112

Multiplication levels 113 and 114 according to the form I i g. 4b entered and further processed with these as explained above.

The resources required for this at the right time for the cycle Control of the functional units according to ί F i g. 4c are not shown for the sake of simplicity.

To switch off the propulsion control device, L on is expediently connected to the output signal of Protective device controllable relay 127 with normally closed contacts 128, 129 and 131 is provided, and when it is activated, the output from the evaluation circuit 56 to the switching valve arrangement 52 the pressure source 53 and possibly to the control valves 23 and 24 leading control signal paths to be interrupted. Next is a button 132 i-> provided, with which the driver can target the propulsion control device 10 for a period of e.g. 20s can switch off.

A timing element 133 which determines this switch-off time period is expediently designed so that it is reset when the ignition is switched off, so that each time the vehicle is started, its Propulsion control device 10 is in the ready-to-regulate state.

One of the propulsion control device 10 according to FIGS. for the state of motion of the driven rear wheels 13 and 14 characteristic acceleration signals ^ o bn and bi. and the spin tendency of these wheels 13 and 14 is deduced from the amounts and the difference between these signals and the reference variable for a propulsion control is determined from this, which is largely analogous to that explained with reference to FIGS. 1 and 2.

An evaluation stage working with evaluation of such acceleration signals can also be used as an additional Functional unit can be provided in the context of a propulsion control device 10, such that ■ »< > Combination of further optimization of both driving safety and the usable propulsive power is achievable.

With reference to Fig.5a and 5b, on their details It is expressly referred to, in the following, the structure of an evaluation circuit is intended 141 represented propulsion control device 140 are explained, which is now specifically for a Combination with an existing ABS system on the vehicle, whose driven wheels 21 and 22 associated brake pressure control valves 23 and 24 (Fig. 1) can assume three functional positions: Basic position for building up the brake pressure, locking position for holding pressure and a reverse position for the Brake pressure reduction is provided

In Fig.5a are with circuit parts of the Evaluation circuit 56 according to FIGS. 1 and 2 comparable or analog circuit parts with the corresponding reference numerals occupied, d. H. the division of the evaluation circuit 141 into a signal processing stage 27, a comparison device 39 and a linking device 42 correspond to that according to FIGS. 1 and 2.

The input stage 142, which receives the output signals proportional to the wheel speed from the speed sensors 16 to 19, generates at its output an output signal vvu which is proportional to the circumferential speed of the left front wheel, at its output 144 an output signal vm. Which is proportional to the circumferential speed of the left (driven) rear wheel at its output 146 an output signal vhr which is proportional to the circumferential speed of the right rear wheel and at its output 147 an output signal vvr which is proportional to the circumferential speed of the right front wheel.

The signal processing .. ife 27 further comprises a first comparison device 148, which is obtained from the comparison of the vvi. and v «/. signals on for the slip A /. of the left rear wheel 22 characteris » ^; cal output signal, and a first differentiating stage 149, which by differentiating the v «/ «Outputs for the acceleration of the right rear wheel and a second comparison stage 152, which outputs an output signal characteristic of the slip Xr of the right rear wheel from the comparison of the v _H r and vwr signals.

In the context of the comparison _{device 39 of the evaluation circuit 141, an A t} comparator 153 and a b _L comparator 154 are assigned to the left side of the vehicle and an A «comparator 156 and an ft ^ comparator 157 are assigned to the right side of the vehicle. The / !(. Comparator 153 and the Ar comparator 156 each have a first output 158 at which a high-level output signal corresponding to a logic one is emitted as soon as the slip A /. Or Ar a first threshold value Ai of reaches or exceeds 4 km / h, for example, and a second output 159 to which a high-level output signal is output when the slip A /. or A «reaches a second, higher threshold value A2 of, for example, 12 km / h or exceeds.

The bf comparator 154 and the ^ comparator 157 also each have two outputs 161 and 162. At their respective first output, the acceleration comparators 154 and 157 emit a high-level output signal when, in the sense of increasing the wheel speed of the driven wheels 13 or 14 effective circumferential acceleration is equal to or greater than a predetermined + δ threshold value of z. B. 1 g («10 ms- ² ). At the second output 162 of the acceleration comparators 154 or 157, a high-level output signal is emitted when the circumferential deceleration of the respective - braked - wheel 13 and / or 14 is equal to or greater than a predetermined threshold value - b of z. B. 0.5 g.

For further processing of the Ai and A2 as well as + b and - ö signals generated for each side of the vehicle, a logic step 163 or 164 is provided in the context of the logic device 42 of the evaluation circuit 141 according to FIG deliver the conditions specified below to one of their three outputs 166, 167 and 168 each, with which the brake pressure control valve 23 and / or 24 assigned to the respective vehicle side in its basic (pressure build-up) position, blocking (pressure holding) position or in its basic (pressure build-up) position or Backward (pressure reduction) control is controllable

The aforementioned conditions are the following:

A pressure build-up signal is to be emitted at the output 166 of the logic circuit 163 and / or 164 if the respective link level 163

and / or 164 _{receives an A 2} signal or a + b and a Λι signal or a + ty and an Ar signal.

At the output 167 of the linking stage 163 or 164, a pressure hold signal is to be emitted when a + b or an A | signal is received at the relevant inputs of the linking stage 163 or 164.

A pressure reduction signal is to be emitted at output 168 of the respective logic stage 163 or f54, if on. the corresponding inputs of these logic stages 163 and 164 either a - b or a - b and an Ai or a - ty and an A ^ signal is present. The outputs 166 and 167 of the two logic stages 163 and 164 are connected to the inputs of a 4-input OR element 169, which emits a high-level output signal as long as a pressure hold or a pressure build-up signal is present at one of its inputs, which is simultaneously indicates that the propulsion control device 140 is effective. With the output signal of the ODFR oil track 169, the fall of which is somewhat delayed by means of a timing element 171, both the activation of the pressure source 53 (FIG. 1) provided for the propulsion control and the activation of the return pump 25 of the ABS system are triggered.

The structure of the to generate the pressure reduction. Pressure hold and pressure build-up signals provided Input linkage stages 163 and 164 are shown below with reference to that shown in FIG. 5b Link level 164 explained in more detail:

The +6 signal of the first comparison device 148 is an input signal of a 3-input AND element 172 which, in addition to a non-negated input 173 to which the + £> signal is applied, has two negated inputs 174 and 176 as further inputs . The first negated input 174 of the 3-input AND element 172 is fed with the output signal of a 2-input UN D element 177, to which the + δ signal and the Ai signal are fed as input signals. The output signal of a further 2-input AND element 178, which has a negated input 179 and a non-negated input 181, is fed to the second negated input 176 of the 3-input AND element. _{The A 2} signal is fed to the non-negated input 181 and the -6 signal to the negated input 179. A second 3-input AND element 182 is also provided, which has a non-negated input 183 and a first negated input 184 as well as a second negated input 186. The output signal of the 2-input AND element 177 is present at this negated input 186. The -6 signal is applied to the first negated input 184 of the 3-input AND element 182; the Ap signal is fed to the non-negated input 183.

A 2-input OR element 187 is also provided, to which the output signals of the two 3-input AND gates 172 and 182 are supplied as the input signal are. The output signal of this OR gate 187 is the pressure hold signal.

A second 2-input OR gate 188 receives as input signals the output signals of the two 2-input AND elements 177 or 178. The output signal of this 2-input OR element 188 is this Pressure build-up signal.

A third 3-input AND element 189 is also provided within the framework of the logic step 164, the has a non-negated input 191 and two negated inputs 192 and 193. The negated Inputs 192 and 193 of this AND element 189 are the output signals of one of the two OR elements 187 or 188 forwarded. At the non-negated input 191, this 3-input AND element 189 receives the fall - '/ erzöger'.e Output signa! of the timing element! 71 or the 4-input OR element 169. By the output signal of the timing element 171 is after the drop in the pressure hold or pressure build-up signals for one more short latency the control signal for the return pump 25 of the ABS system is maintained, so that in a pressure reduction can still take place during this period of time. As soon as this output signal has fallen, it falls then also the pressure reduction signal and the control cycle is ended, with the brake pressure control valves 23 and 24 return to their basic position.

In Fig. 5a only represented by the function blocks 194 and 196 subunits of the signal processing stage 27 and the comparison device 39 of the evaluation circuit 141, which are dependent on threshold values of the vehicle speed (v _a, v _s \, Vsi), the longitudinal acceleration or the transverse acceleration or of cornering display signals, as well as overheating of the wheel brakes 21 and 22 emit a signal that in the sense of a select-low operation of the

•• η propulsion control device 140 the torque-reducing Intervention in the drive unit of the vehicle is triggered when only one de- wheel brakes 21 or 22 is activated, can have the same structure as on the basis of FIG. 1 to 4c explained.

One of these signals characteristic of critical driving situations or operating states of the vehicle the pressure maintenance and / or pressure build-up output signals of the logic stages 163 and 164 appropriately to the torque-reducing intervention

Sub-unit 97 that processes the control signal that is triggered in this way the logic device 42 of the evaluation circuit 141 is shown in detail in the lower right part of the F i g. 5a shown.

In addition 6 sheets of drawings

Claims (24)

Patent claims: 1. Device for propulsion control on motor vehicles in the sense of preventing undesired spinning of the driven vehicle wheels, with a first control circuit which responds to the state of motion of at least the driven vehicle wheels and which, if one of these wheels tends to spin, activates its wheel brake, and with a second control circuit, which mediates a reduction in the output torque of the drive unit when the driven wheels on both sides of the vehicle continue to spin, as well as with a measuring device which detects the vehicle speed and generates a characteristic output signal, characterized in that a threshold value (v _s 1 ) the vehicle speed responsive comparison device (41) is provided. which generates a characteristic output signal when the vehicle speed fv ^ is greater than this threshold value (Vn), that a cornering detection device (69, 76; 94) is provided which emits an output signal characteristic of cornering, and that the simultaneous presence of the for v > v, \ generated output signal of the comparison device (41) and the curve-characteristic signal of the curve-driving detection device (69, 76; 94) with a signal indicating the tendency to spin of a single one of the driven vehicle wheels (13 or 14) that already indicates the "KeduzitiOing des Trip & angssigna! 2. Device according to claim 1,. acharacterized by the fact that the speed threshold value Cv ₁ 1) is approx. 40 km / h 3. Device according to claim 1 or claim 2, characterized in that a second, higher speed threshold value (v, ₂ ) of z. B. 100 km / h can be specified or specified. when this is exceeded, a comparison device (39, 77) generates an output signal mediating the reduction of the drive torque when there is only a single brake control signal indicating the tendency of one of the driven wheels (13 or 14) to spin when driving straight ahead 4. Device according to one of the preceding claims for a four-wheel vehicle with a driven and a non-driven wheel on each side of the vehicle, which are provided with speed sensors, the output signals correlated with the respective wheel speeds, for. B. generate pulse signals with a frequency proportional to the speed, from the processing of which a signal conditioning circuit generates a first slip signal that is proportional to the speed difference of the wheels on one side of the vehicle and a second slip signal that is proportional to the speed difference of the wheels of the other side of the vehicle, the two slip signals as input signals are each fed to a comparator which, when a threshold value Km considered to be permissible is exceeded, generates a control signal for an assigned brake pressure regulating valve that activates the drive wheel brakes on the respective side of the vehicle, and an AND logic circuit that receives the slip signals as input signals is provided, its output signal an intervention in the drive unit in the sense of a reduction in the drive torque mediates characterized in that one of the wheel speed signals of the non-driven wheels z. B. by adding up or averaging within predetermined cycle time intervals Δ ti to a vehicle speed-proportional v-signal processing circuit unit (68) is provided c'sren v-output signal to a comparator (41) is supplied when the v-signal is greater than a predetermined Comparison Schwdlenwert v _sl is an output signal that is generated to one input of two two-input AND elements (47 ■ and 48) . 33) are supplied, and that an actuator can be activated by the output signal of the two AND elements (47 and 48) is provided for reducing the drive torque 5. Device according to one of the preceding claims, characterized in that in the frame the evaluation circuit (26) of the control device (10) two logic elements (34 and 36) are provided from the AND operation of the output signal jev-eils of the two Aw comparators (32 or 33) with the inverted output signal of the other of these comparators (33 or 32) an activation of the wheel brake (21 and / or 22) of the vehicle that tends to spin Generate wheel triggering control signal. 6. Device according to one of the preceding claims 3 to 5, characterized in that a further comparator (77) is provided which generates an output signal as soon as the driving speed ν is greater than a second threshold value v, ₂ , which is greater than the first threshold value v _s i is that the output of this further Ksmparator (77) is connected to the one input of two two-input AND elements (81 and 82), the other inputs of which are each connected to the output of one of the two slip value comparators (32 or 33) are connected, the high-level output signals of the two AND gates (81 and 82) triggering the torque-reducing intervention in the drive unit, and that with the output signal of the cornering detection device (69, 76; 94) an electronic Switching element (84) can be controlled. that. As long as the output signal of the cornering detection device is present, the signal flow from the v, r comparator (77) to the downstream AND gates (81 and 82) mediates and otherwise blocks. 7. Device according to claim 6, characterized in that that the cornering detection device each one the wheel speed of the non-driven Wheels (11 and 12) detecting speed sensors (16 or 17), as well as a comparison device, which is a cornering detection signal from the difference in the wheel speed signals from the speed sensor generated. 8. Device according to one of the preceding claims I to 6, characterized in that the Cornering detection device as a centrifugal force or lateral acceleration measuring device is trained. 9. Device according to one of the preceding claims 1 to 6, characterized in that as Curve drive detection device an electrical responsive to actuation of the steering Switching contact device is provided. 10. Device according to one of the preceding claims 1 to 6, characterized in that the cornering detection device (94) generate an output signal proportional to the expression W-Zi v ² , where fgv and 4v are the frequencies of the output signals of the speed sensor (ί6 and 17) of the non-driven wheels (ti and 12) mean. 11. The device according to claim 10, characterized in that with the output signal of the cornering detection device (94) proportional to the lateral acceleration, a threshold value transmitter (99) can be controlled, the output signal of which is the reference signal for a speed comparator, the output signal of which is one of the slip values when an output signal is simultaneously present. Comparators (32 or 33) mediate the triggering of the torque-reducing control signal, and that the output signal level of the Schwcücnwertgebers (99) opposite to the output signal level of the cornering detection device (94) varies and when _driving straight ahead (low lateral acceleration) a high threshold value v j2 and at high lateral acceleration (fast cornering and / or tight cornering radius) corresponds to a low threshold value v _s \. 12. Device according to one of the preceding claims, characterized in that a further Circuit means (79) responsive to a threshold value of vehicle acceleration are provided is the reduction when this acceleration threshold value is exceeded The output signal which mediates the drive torque is generated. 13. Device according to claim 12, characterized in that an output signal mediating the reduction of the drive torque can be obtained from an AND operation of the output signal of the acceleration comparator (79) with the output signal of a further speed comparator (78). whose comparison threshold Vj is approx. 20 km / h. 14. Device according to one of the preceding claims, characterized in that further a the forward acceleration of the driven wheels (13 and 14) responding comparison device is provided when a predefinable or predefined threshold value is exceeded the circumferential adjustment on one or both of the driven wheels results in a reduction in the Mediating output torque of the drive unit; Output signal and at different The wheel acceleration amounts to a compensatory activation of the wheel brake (21 or 22) of the more accelerated drive wheel mediating output signal generated. 15. Device according to one of the preceding claims, characterized in that the output pressure level ρ of the pressure source (53) of the propulsion control device (10) according to the relationship ρ - (/ 2- / 1)
2 μ _β · F _k ■ mg is selected, where / 1 and h are the maximum vehicle accelerations possible for the lowest and highest possible values of the adhesion coefficients between the road and the wheel, r the rolling radius of the driven wheels (13 and 14), r _m the mean friction radius of the brake disc, μβ The coefficient of friction of the brake linings and Fi denote the cross section of the brake caliper piston of the wheel brakes (21 ^K : w 22). 16. Device according to one of the preceding claims, characterized in that the propulsion control unit (10) can be switched off for a period of time predetermined by means of a timing element (133) and after this period of time it returns to the ready-to-regulate state 17. Device according to one of the preceding claims, characterized in that a Protection device (100, UO) is provided, which in the event of excessive heating of the brakes (21, 22) of the driven vehicle wheels (13,14) an alarm display (107) turns on and if overheating persists the brakes (21, 22); en this activating part of the propulsion control device (10) switches off or at least the threshold for the intervention mediating the prevention of the propulsive torque lowers in the drive unit. 18. Device according to claim 17, characterized in that the brake discs of the driven Wheels with thermoelectric temperature ju ture sensors, especially thermocouples are whose temperature-proportional output signals via sliding contacts of the processing unit the protective device (100) are fed. 3 ") 19. Device according to claim 17, characterized characterized in that the brake linings of the wheel brakes (21, 22) with temperature sensors (102, 103) are provided whose electrical output signals are a measure of the brake disc temperature. • »0 20. Device according to claim 9, characterized characterized in that the temperature sensors (102 and 103) in for receiving wear sensors provided recesses of the brake pads or are attached to the wear sensors themselves. * '> 21. Device according to claim 19, characterized characterized in that the wear sensors are designed as thermocouples, their electrical Interruption or ground connection mediated by the brake disc, the wear indicator signal '"' triggers. 22. Device according to claim 17, characterized in that within the scope of the protective device (100; 110) at least one multiplication level (113 or 114) 'is seen, which gives a shock i ' p, N, generated proportional output signal, where p, the for successive cycle time interval Δι » whose total duration corresponds to the activation time of the respective wheel brake (21 or 22), determined value of the brake fluid pressure and N, which for the bo individual Zykiuszeitintervalle determined R & dum · rotations, and that a comparator stage (118, 115) is provided which produces an alarm indication signal when this Ausgangssigna! exceeds a predetermined threshold value, which is a measurement for a limit temperature to which the wheel brake (21 or 22) may be pointed. 23. Device according to claim 22, characterized in that the wheel brake cylinder of the driven vehicle wheels (13 and 14) are each provided with a pressure sensor (111 and 112), their electrical pressure output signals as input signals of the multiplication stage (113, 114) are forwarded. 24. Device according to claim 22, characterized in that a computer stage (126) is provided is the output signals characteristic of the vehicle acceleration as input signals receives and from it by electronic evaluation of the relationship